The present invention relates to an automobile vehicle door of the type comprising a box structure, a module adapted to be applied on the periphery of an opening formed in the inner side of the box structure, the module carrying components including an acoustic enclosure with a loudspeaker, and an inner trim panel covering the module.
It is known that there are two types of acoustic enclosures for high fidelity sound systems: the closed enclosures which define a closed box containing the speaker which excites the air, and the so-called "bass reflex" enclosures in which the volume of air behind the speaker communicates with the front side of the enclosure through a vent.
In the closed enclosures, the wave emitted by the rear side of the speaker must be absorbed. Only the wave emitted by the front side of the speaker is sent in the direction of the listener, so that all the bass frequencies are eliminated.
On the other hand, with the bass reflex enclosures, the volume of air is no longer closed but open and the wave emitted by the rear side of the speaker is re-emitted toward the front with a judicious arrangement of volumes and lengths of the vent duct so that the frequency of excitation of the rear volume of air is lower than the frequency of resonance of the speaker. In this case, the enclosure emits highly amplified low frequencies. The invention does not concern the choice of the volumes which are considered to be known.
Heretofore, in vehicle doors of the aforementioned type, the speaker was mounted on the sheet metal structure of the door which forms a sealed closed cavity absorbing the rear wave. This arrangement does not permit obtaining strong bass frequencies so that the acoustic efficiency in low frequencies is not as satisfactory as in the case of the bass reflex enclosures. Further, the interior of the doors is not watertight which constitutes an obstacle to the installation of acoustic enclosures of the bass reflex type on a vehicle door since in this case water and noise could enter the compartment of the vehicle through the vent.